Non-grounded spark-plug.



J. A. ROSE.

NON-GROUNDED SPARK PLUG,

APPLICATION FILED JAN. 11. 1918.

l ,299,035. Patented Apr. 1, 1919..

ITLUQ'VUITOY'I 25 CL. Rage PATENT :msnniosnjonsr. LOUIS, mrssonnn; mi a To all cukomz't may concern:

Be ,i'tknown that I, JAMES A. Rose, a citizen of the United States, residing at St.

Louis, in the State of Missouri, have invented c'ertain new and useful Improvements in Non-Grounded Spark-Plugs, of which the following is a specification containing a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates to sparklugs which are used in firing the charge of explosive in the cylinders of automobile motors, air-plane engine's,and in all other hydrocarbon power plants; and my invention consists in the novel construction and combination of parts hereinafter fully described and particularly pointed out in the claim found at the end Heretofore, in all spark-plugs known to me, one of the two points (between which the spark is formed) has been grounded to some portion of the engine, which acted as a conductor for electricity between the grounded point and the source of electricity, sothat but a single terminal was provided at the top or exposed end of the plug, and

if the flexible conductor became accidentally disconnected from said single terminal and, again' accidentally momentarily connected therewith while the metallic part of the plug is in contact with some metallic portion of the en 'ne, a dangerous spark has been produced etween the twospark points of the lug, causing accidental explosions and amage. a

The object of my invention is to provide a non-ground spark plug, which will obviatethe danger of accidental explosions of gasolene vapor while the spark tached from its usual position an carelessly placed in the vicinity ofgasol'ene, with its grounded point electrically connected to a source of electricity, such as a magneto, battery, or dynamo." a

.In the drawings, 1;;

Figure 1 is a vertical section through my improved spark plug, and I Fig. 2 is a side-elevation of the pointcarrying body of insulation, detached from the plug. The numeral 1 designates the usual plug casing, which is ma e of metal, with a threaded end 2, for the well-known purpose of permitting the plug to be screwed into the combustion chamber of the engine.

' Specification of Letters Patent.

ug is de- V Patented A ,1, 9 19., Applicationmed llanuarylL llp. I Seria1 No.211,351. I I

cylindrical body of stable estate:

(such as porcelain or mica) 3 is provided with an enlargement 4 at about the center of its length, and t'wo point wires '5 and 6 are molded, cast, or otherwise securely placed within said body (preferably during the molding o'peration), so that said wires will pass-endwisethrough saidbody, and their far as possible the weakening ofsaid body by the said bend or kink in said wires.

The usual stuffing-box glandlO is screwed into the upper end of said casin 1, to engage a suitable gasket or packing 11, to make a tight joint between said casing and the said body of insulation 3, which carries both of said points.

The usual gasket 12 is also used to make a. tight joint, and to make a soft or yielding seat for the said body of insulations' enlargement4, at the point where said body rests at the base of the socket in said casing.

The upper, or outer, end of the said body 3 is formedwith an integral flat extension 14, which projects a considerable distance beyond the main body, and acts as a shield to prevent a spark from jum ing across the space between the terminals 0? 5 and 6, and said extension 14: also acts to brace the terminals, in a manner now to be described.

Set on the upper end of said body 3, on opposite sides of the said extension 14, are brass terminal-caps 15, which are semicircular in plan-view, and have integral screws 16 provided with clamping-nuts 17, by means of which the wires from the magneto, battery or other source of electricity are connected to said terminal-caps, the caps them-. selves being connected to the upper ends of thesaid wlres 5 and 6 by the ends of said wires being inserted through perforated ears 18 which depend from the underside of said caps, and said wires may be further and more securely connected to said ears by means of solder, or in any other known way, referably before the material of the said ody 3 is molded around the wires.

the said wires 4 end to end, and having ends which project.

The operation pf my invention will/be. clear to those skilled in the art, without further description, I claim:'

An improved spark-plug, composed -of-ametallic' casing, a body of insulation seated in said casing and having at one, end a flat extension which projects a suificient distance to act asa shield and brace fol-the terminals of the plug; metallic terminal caps set on up osite sides of said extension andprovi ed with suitable terminal clamps-t0 re:

ceive the magneto or battery wires; and two 7 separate oint wires embedded-in said insulation an extending through the same from Copies of thli patent may be obtained-tor m. cent: each, by mid -chinks}: :Wuh lngtomll. 0.

beyond the ends lof said body of insulation,

and form at one end'spark-points, the op-' posite ends of said wires being connected to said'terminal-capson opposite sides oithe said extension of said ody of insulation,

' and the saidwires beingprovided with cirname to this specification in pr sence of two subscribing witnesses. p

JAM S -I QSE- Witn'esses FRANCES Ho Jon C. Hreiioiv.

a'gonnmm r a: raging, 

